Conventional techniques for concentrating, collimating and/or focusing microwave and millimeter-wave energy generally use curved surfaces and apply optical theory. To generate coherent energy having a single polarization, dielectric lenses, such as a Lundberg lens, have been used. These lenses are complex and difficult to construct. Furthermore, it is difficult to generate sufficiently coherent and/or collimated energy for some applications with these conventional lenses.
Thus there are general needs for improved apparatus and methods that provide for concentrating, collimating and/or focusing microwave and millimeter-wave energy.